Comparative study of the isolation of human immunodeficiency virus from the lung and peripheral blood of AIDS patients

HIV-AIDS in Minorities

HIV-AIDS has disproportionately affected minority populations in the United States. Significant disparities in case rates and mortality have been noted. This article reviews the magnitude of the problem and the many factors involved in the development and perpetuation of these disparities. Possible measures to help correct the problem are also reviewed.

Analysis of human lung endothelial cells for susceptibility to HIV type 1 infection, coreceptor expression, and cytotoxicity of gp120 protein

The lung represents a potential target during HIV infection, and the onset of AIDS is associated with severe pulmonary complications in many patients. T-lymphocytes and alveolar macrophages form the majority of HIV-infected cells in the lung. However, other cell types in the lung could participate in HIV-mediated lung pathology and their role has not been investigated. The aims of this study were to determine if human lung microvascular endothelial cells (HLMEC) express HIV receptor and coreceptors, and if HIV can directly infect HLMEC. Specifically, we wished to determine if these cells constitute a viral reservoir in the lung, and if HIV-1 envelope proteins induce cytotoxic effects on HLMEC. Our results showed that by flow cytometry, HLMEC failed to express any CXCR4 or CCR5 on their surface. In contrast, RT-PCR revealed the presence of CXCR4 and CCR5 mRNA, but not CD4 in HLMEC. Two dual-tropic HIV-1 isolates failed to infect HLMEC in vitro, as determined by (1) p24 antigen capture ELISA, (2) reverse transcriptase assay, RT-PCR, and (3) DNA PCR. However, a recombinant HIV-1 gp120 preparation induced apoptotic cell death of HLMEC. These data support the hypothesis that no productive HIV-1 infection of HLMEC occurs in vitro. This suggests that in vivo, HLMEC may not be a major reservoir of HIV in the lung and the primary route for HIV invasion of the lung. Thus, while other mechanisms must play a role in HIV invasion and subsequent dissemination in the lung, lung endothelial cells do represent potential targets for the lethal effects of HIV viral proteins.

Activation-inactivation of HIV-1 in the lung

The lung is prominently afflicted during the course of HIV-1 disease by both infectious and noninfectious complications. Direct or indirect effects of HIV-1 are likely central to the pathogenesis of these complications. Thus, any changes in viral load locally would negatively impact on the lung. This review focuses on the endogenous influences (immune effector cells, surfactant) and the exogenous factors (including infections such as tuberculosis and noninfectious exposures like cigarette smoke) that may contribute to activation or inactivation of HIV-1 in the lung.

The growth and the control of human immunodeficiency virus in the lung: implications for highly active antiretroviral therapy

In recent years, it has become apparent that the lung is an important niche for the proliferation of human immunodeficiency virus (HIV), which may have implications for highly active antiretroviral therapy (HAART). The lung itself is a major site for the opportunistic infections associated with the progression to acquired immune deficiency syndrome (AIDS), specifically Pneumocystis carinii, Myobacterium tuberculosis and pyogenic bacteria. These cases of active pulmonary complications are direct indicators of enhanced progression to AIDS-defining illness and increased morbidity and mortality. It is therefore essential that the interaction between the lung and HIV is fully understood. Recent research indicates the lung may be a major sanctuary for the virus, with distinct evolution and replication in contrast to other target organs for HIV. In this review, we will discuss the recent findings of HIV infection, evolution, host factors involved in the control of HIV within the lung and the impact this may have on current therapy.

Comparison of the sensitivities of two non-isotopic reverse transcriptase (RT) assays for human immunodeficiency virus type 1 RT

The sensitivities of two reverse transcriptase (RT) assays, an enzyme-linked oligonucleotide sorbent assay (ELOSA)-RT assay and a non-radioisotopic (non-RI) RT assay were compared. For measuring recombinant HIV-1 RT, the ELOSA-RT assay was 8 times less sensitive in dilution endpoint and 16 times less sensitive in measurement of RT from pelleted HIV-1 than the non-RI RT assay. Higher level of interference by an RNA-DNA hybrid observed in the former assay may indicate that the reduction in sensitivity was due to the presence of viral RNA in the sample of pelleted virus. The ELOSA-RT assay was interfered with to a great extent than the non-RI RT assay by fetal bovine serum and thus may be unsuitable for measuring RT from HIV-1 in a culture supernatant.

Comparable sensitivities for detection of HIV-1 reverse transcriptase (RT) and other polymerases by RT assays requiring no radioisotopic materials

An improved non-radioisotopic (Non-RI) reverse transcriptase (RT) assay with a template-primer-immobilized microtiter plate is described, which has greater sensitivity than the former Non-RI RT assay previously described. Non-RI and commercially available non-radioactive (Non-RA) RT assays were compared for their ability to detect various polymerases. Two RTs from Rous-associated virus 2 (RAV-2) and avian myeloblastosis virus (AMV), one polymerase from Escherichia coli (Pol-I) and one recombinant RT of human immunodeficiency virus type 1 (HIV-1) were assessed. Two HIV-1 samples in a culture supernatant and pelleted virion suspended in Triton X-100 solution were measured. The Non-RI RT assay was one hundred times more sensitive by RAV-2 and Pol-I polymerases, and one thousand times more sensitive by the Non-RA assay than by the AMV RT. The Non-RI RT assay was 10, 16 and 64 times more sensitive than the Non-RA assay for measuring recombinant HIV-1 RT, pelleted virus and virus suspended in culture medium, respectively. To explain the discrepancy, it is shown that free biotin, such as in culture medium, disturbs the assay system of the Non-RA RT assay, but not the Non-RI assay. The present assay can be used to clarify the inhibitory mechanism of an anti-HIV-1 substance.

HIV-1 proviral DNA copy number in peripheral blood leucocytes and bronchoalveolar lavage cells of AIDS patients

In this study we have determined by polymerase chain reaction (PCR) the quantity of HIV-1 proviral DNA in cells obtained by bronchoalveolar lavage (BAL) from the lung of HIV-1+ individuals. This has been compared quantitatively with the proviral DNA in peripheral blood leucocytes (PBL) obtained simultaneously from the same patients. The mean HIV DNA copy number per 10(6) cells was 391 for PBL, with a range of 1-9000, and 2971 for BAL cells, with a range of < 1-70,000. The quantity of HIV DNA detected in BAL cells was higher than that detected in the corresponding PBL samples in 44 out of 78 (56%) individuals, whilst more HIV DNA was detected in the PBL compared with BAL cells in 14 out of 78 (18%) patients. In both BAL and PBL higher levels of HIV DNA were detected in the adherent (monocyte/macrophage) enriched cell populations compared with other non-adherent cells (leucocytes). A direct relationship between HIV DNA copy number and ability to recover infectious HIV progeny in vitro by co-cultivation with cord blood leucocytes was found for both PBL and BAL cells. Individuals known to be receiving azidothymidine treatment had a lower mean HIV DNA load in all cell fractions compared with those patients on no antiretroviral therapy.

Relation of HIV-I in bronchoalveolar lavage cells to abnormalities of lung function and to the presence of Pneumocystis pneumonia in HIV-I seropositive patients

BACKGROUND

HIV is present in bronchoalveolar lavage cells of some but not all HIV seropositive patients. Abnormalities of lung function have been described in such patients in the absence of clinically overt pneumonia or other respiratory infections. It is possible that the presence of HIV in alveolar macrophages could account for these abnormalities. It is also possible that the presence of HIV in alveolar macrophages contributes to immunosuppression and an increased incidence of opportunistic infections.

METHODS

This was a prospective study of 157 HIV seropositive patients requiring diagnostic bronchoscopy for investigation of new respiratory symptoms, chest radiograph abnormality, or pneumonic illness. Presence of HIV in bronchoalveolar lavage cells obtained at diagnostic bronchoscopy was determined by polymerase chain reaction to detect proviral DNA and in vitro cocultivation to detect productive virus infection. With these two techniques the presence or absence of HIV in bronchoalveolar lavage was compared with the presence of abnormalities of lung function or presence of Pneumocystis pneumonia.

RESULTS

HIV was detected in bronchoalveolar lavage cells in 65% of patients by means of the polymerase chain reaction and 59% with cocultivation. With both methods of detection there was no association between the presence or absence of HIV and the presence of Pneumocystis pneumonia; nor was there a relation between the presence of HIV and abnormalities of lung function.

CONCLUSION

The presence of HIV in bronchoalveolar lavage cells does not predispose to an increased incidence of Pneumocystis pneumonia; nor does it contribute to abnormalities of lung function.